Predictors of progression of renal functions in patients with chronic obstructive pulmonary disease (COPD)

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Introduction
Chronic obstructive pulmonary disease, or COPD, is a prevalent, treatable, and preventable illness marked by persistent respiratory symptoms and restricted airflow because of abnormalities in the airways and alveoli that are typically brought on by prolonged exposure to harmful particles or gases [1].Compared to the general population, COPD patients have a higher chance of getting CKD [2].Common risk factors for the beginning of chronic kidney disease (CKD) include ageing, diabetes, arterial hypertension, and obesity [3].
COPD patients have a higher risk of developing CKD than the general population [3].The most prevalent risk factors for the new start of chronic kidney disease (CKD) are age, diabetes, arterial hypertension, and obesity.
Atherosclerotic damage from the activation of pro-inflammatory and pro-oxidant pathways that result in pathologic alterations in renal circulation is one of the causes of chronic kidney disease (CKD) [4].
Pulmonary cells can produce many cytokines, reach the systemic circulation, target other organs, and also produce inflammatory effects [5].
Atherosclerotic damage from the activation of pro-inflammatory and pro-oxidant pathways that result in pathological alterations in renal circulation is one of the causes of chronic kidney disease (CKD) [4].In addition to producing a wide range of cytokines, pulmonary cells can target other organs, enter the systemic circulation, and cause inflammation [5].

Angiotensin-converting enzyme (ACE)
expression and pulmonary vascular permeability can both be impacted by renal ischemia.This can impair the function of ion channels, which are in charge of reabsorption of fluids at the level of pulmonary alveoli [6] So, the current study aimed to forecast the decline in renal function in individuals suffering from COPD.

Subjects
From
• The existence of systemic autoimmune diseases or chronic inflammation.
A relevant parameter, such as the estimated glomerular filtration rate (eGFR), whose variability correlates with a poor prognosis, was used to assess the decline in renal function [7].
Following each participant's medical consent, the following information was gathered for each patient: • Full medical history, including the MMRC and CAT scores.
• Clinical examination (both local and general chest exams).
• Spirometry was performed using the (spirobankπ) device in the pulmonary function unit of the chest department at Fayoum University Hospital.
• BMI: Body mass index is a statistical measure that calculates body fat in both males and females of any age by considering a person's height and weight.The formula for calculating BMI is weight (in kilograms) divided by height (in meters squared), or weight (in kg)/height^2 (in m^2).
• eGFR: The estimated glomerular filtration rate is a way to assess the ability of the kidneys to filter toxins from the blood balance of fluids.
It is one of the primary diagnostic methods for detecting and managing kidney diseases.
• Assessment of systolic and diastolic blood pressure.
When the anticipated frequency is less than five, an exact test was utilized instead [9].
Quantifiable variables are correlated using the Spearman correlation coefficient [10].P-values were regarded as statistically significant if they were less than 0.05.

Results
In B and E (47% and 40%), respectively, but lower in group A (28%).The level of uric acid was <6.5 mg/dl, which is higher in patients with grades III and IV (41.51%) than grade I and II (386.4%)(Figure 1).to-creatinine ratio in the assessment of chronic COPD [12].All of the patients were in the stable phase of the disease, had not experienced any exacerbations in the previous three months, had not changed their treatment plan, and had not developed lower respiratory tract infections.
UA is known to be linked to markers of systemic inflammation, bronchoconstriction through endothelin-1 activation, and oxygen desaturation.Lower and higher levels of UA have been identified as risk factors for obstruction of the airways.
Themeanuric acid values in our study were 6.39±2.07.deterioration in renal function had a statistically significant difference in creatinine [11].
Our findings also concur with those of Elmahallawy and Qora (2013), who conducted a study on the prevalence of chronic renal failure in patients with COPD [14].They found that the mean serum creatinine concentration was 0.85 ± 0.34 mg/dL for all patients, and that the COPD group's mean serum creatinine concentration was significantly lower than the control groups.
That mismatches with Nishiki et al. (2021), as there were no appreciable variations in serum creatinine levels between stage III and stage IV COPD patients in spite of a marked decline in pulmonary functioning [15].

Conclusion
Serum creatinine (S.cr) is regularly used to diagnose and evaluate renal injury.Patients with COPD have a higher risk of developing CHD than normal populations.This risk can be determined by a variety of approaches, including laboratory examination of serum creatinine, uric acid, albumin, and eGFR.We recommend that multicentered studies be needed to evaluate, predict the worsening of renal function, and follow up with COPD patients over a period of time to evaluate the progression of renal functions.

Ethical consideration and patient consent:
The Faculty of Medicine Research Ethical Committee approved the study's goals, the examination, the investigation that will be conducted, the confidentiality of their information, and their right to decline participation were all explained to the participants.
Funding: This study is not funded.

Conflicts of Interest:
All authors declare they have no conflicts of interest.

Figure 1 :FUMJ
Figure 1: The level of Uric acid <6.5 in different and grades classes of COPD.

Table 1 :
The statistical comparison between FEV1 in COPD patients and BMI, eGFR, creatinine, and uric acid.
2.07.The level of uric acid<6.5 mg/dl was found in 53% of COPD patients in our study.By evaluating the uric acid level in different classes and according to the severity of airway obstruction, we found that the level of urea acid<6.5 mg/dl is higher in patients with classes